Why do young infants fail to search for hidden objects?

Abstract

Infants less than 8 months old appear to lack the concept of object permanence because they fail to search for hidden objects. However, when looking rather than reaching is assessed, infants appear to have object permanence long before 8 months. One explanation for the discrepancy is that young infants lack the means-end motor skill to retrieve objects hidden by covers. The present research tested the object permanence deficit hypothesis against the means-end deficit hypothesis. Direct-reach search tasks were used, which should result in increased search by young infants if the means-end deficit hypothesis is correct. In Experiment 1, 6- and 10-month-old infants were presented with an object visible in water, partly visible in milk hidden in milk, or hidden under a cloth. As predicted by the object permanence deficit hypothesis, 6-month-old infants were less likely to search when the object was hidden than when it was visible or partly visible, but there were no differences at 10 months. The means-end deficit hypothesis prediction that younger infants would be less likely to search when the object was hidden by a cloth than when it was hidden by milk was not confirmed. In Experiment 2, 6- and 10-month-old infants were presented with an object visible behind a transparent curtain, partly visible through a hole in an opaque curtain, partly visible (fit flashlight) under a cloth, and hidden behind a completely opaque curtain. As predicted by the object permanence deficit hypothesis, 6-month-old infants were less likely to search when the object was hidden than when it was visible or partly visible, but there were almost no differences at 10 months. Unexpectedly, measures of locomotor ability were not reliably related to infants' search at 6 months. In a comparison of the cloth event of Experiment 1 and the flashlight event of Experiment 2, half the results indicated that 6-month-old infants were more likely to search in the partly visible event. The results are more consistent with the object permanence deficit hypothesis than with the means-end deficit hypothesis.